LONG-TERM DEBT (Details 2) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Mar. 31, 2017	Mar. 31, 2015
Long-term debt
Payments of Financing Costs		$ 17,120	$ 11,079
Outstanding borrowing amount	$ 1,432,013	1,432,013			$ 1,196,300
Transfer of Financial Assets Accounted for as Sales, Amount Derecognized	$ 0	0			78,006
Senior Notes Due 2025 [Member]
Long-term debt
Debt Instrument, Repurchase Obligation Due to Change of Control, Percentage of Original Principal	100.00%
Payments of Financing Costs	$ 8,779
Outstanding borrowing amount	500,000	500,000			0
Receivables Purchase Agreement [Member]
Long-term debt
Line of Credit Facility, Maximum Borrowing Capacity	90,000	90,000
Term loan credit agreement
Long-term debt
Outstanding borrowing amount	0	0			309,375
Revolving credit facility
Long-term debt
Line of Credit Facility, Maximum Borrowing Capacity	800,000	800,000		$ 850,000	1,000,000
Payments of Financing Costs		$ 633
Unamortized financing costs prior to amendment						$ 13,226
Debt Instrument, Description of Variable Rate Basis		LIBOR
Outstanding borrowing amount	117,393	$ 117,393			29,999
Letters of Credit Outstanding, Amount	30,302	30,302			27,240
Borrowing capacity under revolving credit facility after reductions for borrowings and letters of credit outstanding	652,305	652,305
Asset-backed Securities [Member]
Long-term debt
Line of Credit Facility, Maximum Borrowing Capacity	125,000	125,000		$ 225,000	175,000
Outstanding borrowing amount	$ 88,800	88,800			112,900
Program fee on the amount outstanding (as a percent)	0.40%
Line of Credit Facility, Commitment Fee Percentage	0.40%
Percentage of line of credit on which commitment fees are charged (as a percent)	100.00%
Capital Lease Obligations [Member]
Long-term debt
Outstanding borrowing amount	$ 61,480	61,480			72,800
Senior notes due 2021 [Member]
Long-term debt
Debt instrument principal amount					375,000
Outstanding borrowing amount	375,000	375,000			375,000
Notes Payable, Other Payables [Member]
Long-term debt
Outstanding borrowing amount	$ 7,978	$ 7,978			$ 7,978
Minimum [Member] | Receivables Purchase Agreement [Member]
Long-term debt
Program fee on the amount outstanding (as a percent)		0.65%
Minimum [Member] | Revolving credit facility
Long-term debt
Debt Instrument, Basis Spread on Variable Rate	1.50%
Maximum [Member] | Receivables Purchase Agreement [Member]
Long-term debt
Program fee on the amount outstanding (as a percent)		0.70%
Maximum [Member] | Revolving credit facility
Long-term debt
Debt Instrument, Basis Spread on Variable Rate	3.50%
Commitment fees (as a percent)	0.50%